Enrichment device for air valve carburetor



March 7, 1967 I A. H. WlNKLER 3,307,837

ENRICHMENT DEVICE FOR -AIR VALVE CARBURETOR Filed Sept. 13, 1965 119 ll 4 i" INVENTOR.

ATTUFNEY United States Patent 3,307,837 ENRICHMENT DEVICE FOR AIR VALVE CARBURETOR Albert H. Winkler, Elmira, N.Y., assignor to The Bendix Corporation, a corporation of Delaware Filed Sept. 13, 1965, Ser. No. 486,983 Claims. (Cl. 26144) The present invention relates to an air valve or constant vacuum type of carburetor land, more particularly, relates to a carburetor of the air valve type which includes a device for providing power enrichment.

It is an object of the present invention to provide a novel device for improving the fuel economy of an air valve canburetor.

It is an object of the present invention to provide a novel device for enriching full throttle fuel-air mixture and leaning out part-throttle fuel air mixture of an air valve carburetor.

It is a further object of the present invention to provide a novel structure for power enrichment of an air valve carburetor which may be operated either manually or by manifold vacuum or by the throttle plate position.

It is a still further object of the present invention to provide a novel enrichment device for an air valve carburetor which varies the fuel metering rate without changing the relative position of the fuel metering needle in the fuel metering orifice.

It is a still further object of the present invention to provide for the release of hot fuel vapor without the necessity for changing the relative positions of the fuel metering needle and the fuel metering orifice.

It is another object of the present invention to provide a novel device for controlling fuel-air mixture ratio in an air valve carburetor by controlling the pressure in the fuel chamber.

Additional objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a side elevational view of an air valve carburetor, partly in section and broken away, being an embodiment of the present invention.

FIGURE 2 is a view of the linkage for regulating the fuel chamber pressure valves by means of the throttle valve position; and

FIGURE 3 is a view of a linkage for regulating the fuel chamber vent valves in response to manifold vacuum.

Turning now to FIGURE 1, the numeral 11 generally designates an air valve type of carburetor having a body 12 with an induction passage 13 formed therein. The inlet extremity of the induction passage is adapted for connection to a source of air, while the outlet extremity 16 of the induction passage is adapted for connection to the engine manifold (not shown). A bridge 17 is formed intermediate of the inlet and outlet extremities of the induction pasage and has formed therein a fuel metering orifice, generally designated as 18. A throttle valve 19 for controlling the admission of the fuel-air mixture to the engine is rotably supported in the passage adjacent to the induucti-on passage outlet by a shaft 20.

The body 12 supports an air valve adjusting device which consists of a two-part chamber, generally designated at 21. The lower side 22 and the upper side 23 of the chamber 21 are separated by a flexible diaphragm 24 and a variable choke piston 26. The lower side or first chamber 22 is in communication with a source of air at a referenced pressure, generally substantially atmospheric pressure. Air at the reference pressure is communicated to the chamber 22 by a conduit 27. The upper side or second chamber is in communication with a source of air at subatmospheric pressure when the engine is operating by a conduit or orifice 28 opening between the hollow interior of the choke piston and the induction passage intermediate of the needle valve 35 fixedly connected to the piston and the throttle valve 19. The piston is guided in its movements by a support 29 depending from the top of the chamber 21 which houses therein a dashpot member 31 connected within a hollow sleeve member .32 of the choke piston. A calibrated spring 33 or the weight of the assembly normally biases the piston toward a choked position. The needle valve 35 which is supported by the piston 26 is adapted to extend into the fuel orifice 18 for regulating the admission of fuel into the induction passage 13 in response to the mass of air passing to the choke area between the bottom of the choke piston 26 and the top of the bridge 17. Metering needle 35 and the fuel orifice 18 cooperate to control the extent of fuel orifice exposure to pressure in the passage. When the throttle valve is in the closed position (indicated by solid lines), the choke piston will substantially close off the induction passage and no air will flow across the bridge. When the throttle valve assumes a wide open or full power position (as illustrated by dotted lines), the pressure differential in the air valve adjustment device 21 will cause the choke piston 26 to be retracted the maximum amount into the chamber 22, thereby allowing the greatest mass air flow to take place and concomittantly, the fuel orifice will be restricted by the needle valve to the least degree.

It is well known that when the engine operates at Wide open throttle or full power, engine manifold vacuum will be at its lowest value and when the engine operates at idle or near idle, the engine manifold vacuum will be at its greatest value.

As is well known, the air valve carburetor, as described above, provides a fuel-air mixture ratio which is generally a function of air flow. To vary this mixture ratio for a given air flow, it is proposed to vent the fuel chamber 40 in the following manner. An impact vent or conduit 44 interconnects the fuel chamber 40 to the induction passage 13. The impact conduit or tube 44 has an outlet 47 upstream of the bridge 17 which opens substantially only to the upstream side of the passage. A suction tube or conduit 46 interconnects the fuel chamber 40 and the induction passage 13 upstream of the bridge 17. The suction tube or conduit 46 has an outlet which is opened substantially only to the downstream side of the passage. A first valve or impact conduit valve 48 is rotatably mounted on a shaft 52 in the impact conduit 44. A suction conduit valve or second valve 50 is rotatably mounted on a shaft 54 disposed in the suction tube or conduit 46. A flange or extending portion 45 is formed to or connected to the choke piston 26 and extends over the outlet 49 of the suction conduit 46 to reduce air pressure in the vicinity of the suction tube outlet 49 when air is flowing in the passage 13. In operation, when it is desired to enrich the fuel-air mixture, the second vent valve 50 is closed and the first vent valve 52 is opened, maintaining the chamber 40 at approximately the same or a higher pressure relative to the static pressure of the flowing air in the vicinity of the impact tube 44. Conversely, when it is desired to lean out or reduce the fuel-air mixture, the first vent valve 48 is closed and the second valve 50 is opened,

thus relatively lowering the pressure in chamber 4% and thereby leaving out this fuel mixture. This relative enriching or leaning out effect will be effective at any mass air flow; thus the device may be operative to enrich the fuel-air mixture at relatively-low manifold vacuum or at relatively-high manifold vacuum or at either relativelyopen or relatively-closed throttle valve position.

FIGURE 2 shows a linkage for controlling the position of the first and second vent valves through direct connection to the throttle valve shaft 20. An arm 56 is rotatably connected to the throttle valve shaft 20, moving a second arm or linkage 58 which is linked to shaft 54 and, in turn, linked to shaft 52 by linkages 60, 61 and 62 respectively. With the linkages in the positions shown in FIGURE 2, the impact and suction tubes would be operative to lean out the fuel-air mixture when the throttle valve is operating between the closed and some predetermined throttle open position before reaching the full open travel of the throttle valve.

Those skilled in the art will readily appreciate that the linkages could be conected in the reverse direction so that the fuel-air mixture ratio could be enriched at a throttle position from closed throttle to a predetermined partially opened throttle.

FIGURE 4 shows a linkage for controlling the position of the vent valves 48 and 5ft through direct connection to manifold vacuum. Such a device has a conduit 70 for conducting manifold vacuum to the vacuum motor 72 which has a spring-biased piston 74 which is connected through linkages 80, 82, 84 and 86 to the first and second vent valves shafts 52 and 54 respectively. Depending on which way the link 80 is connected to lever 82 on shaft 54 will determine whether enrichment will occur at either low or high vacuum. FIGURE 4 shows the vacuum motor acting as a low vacuum power enrichment device.

It can readily be appreciated that the present invention accomplishes its stated objects. Enrichment of a fuel-air mixture or leaning out of the fuel-air mixture may be; at any time, obtained through a mechanical linkage to control the position of the vent valves 48 and 50. Similarly, the position of the first and second vent valves may be linked either to the throttle valve position or manifold vacuum condition. The present invention is simple, effective, efiicient and inexpensive. Those skilled in the art will appreciate that the flange or extending portion 45 of the choke piston 26 is not a necessary part of the pres ent invention; however, it is useful to increase the reduced pressure effect in the vicinity of the vacuum conduit 46. The degree of fuel control may be varied by altering both the absolute and relative sizes of the conduits 44 and 46. Further control may be had by altering the shape and position of the outlets 47 and 49 of the impact and suction conduits respectively. The float chamber vent system, disclosed by the present invention, has the advantage of minimizing float chamber pressure variations caused by fuel vapor entering the float chamber through the fuel system. Although certain structures have been shown and described in detail, it will be understood that changes may be made in the design and arrangement of parts without departing from the spirit of the present invention.

I claim:

1. In an air valve carburetor the combination of:

a body having a fuel-air induction passage;

a fuel orifice opening in the passage;

air valve means mounted for reciprocal movement in the passage;

fuel metering means connected to the air valve means,

said fuel metering means adapted to cooperate with said orifice to control orifice exposure to pressure in the passage;

a fuel chamber means for supplying fuel to said orifice;

a throttle valve means in the passage for controlling the introduction of the fuel-air mixture to the engine; an impact vent means for communicating said fuel chamber means to substantially atmospheric pressure;

a suction vent means for communicating said fuel chamber to a reduced pressure; and

control means for selectively opening and closing said impact vent means and said suction vent means to regulate the fuel-air mixture supplied to the engine.

2. The device described in claim 1 wherein:

said impact vent means comprises an impact conduit interconnecting the fuel chamber to the induction passage upstream of the fuel orifice, said impact tube having an outlet open on the upstream side of the passage; and

a valve member mounted in said impact conduit for opening and closing said conduit.

3. The device described in claim 2 wherein:

said control means is operative to position the impact conduit valve in responsive to engine pressure.

4. The device described in claim 2 wherein:

said control means is operative to position the impact conduit valve in response to throttle valve position.

5. The device described in claim 1 wherein:

said suction vent means comprises a suction vent conduit interconnecting the fuel chamber to the induction passage upstream of the fuel orifice having an outlet open on the downstream side of the passage; and

a valve member mounted in said suction conduit for opening and closing said suction conduit.

6. The device described in claim 5 including further:

said air valve means having an extending portion disposed in the induction passage to decrease the pressure in said induction passage in the vicinity of the suction conduit outlet.

7. The device described in claim 6 wherein:

said control means is operative to position the suction conduit valve in response to engine pressure.

8. The device described in claim 6 wherein:

said control means is operative to position the suction conduit valve in response to throttle valve position.

9. In an air valve carburetor the combination of:

a body having a fuel-air induction passage;

a bridge means disposed in the passage;

a fuel orifice disposed in the bridge means having an opening in the passage;

an air valve means mounted in the passage for reciprocal movement toward and away from the bridge means;

a fuel metering needle means connected to the air valve gneans adapted to move reciprocally in the fuel oria throttle valve means in the passage downstream of the bridge means for controlling the introduction of the fuel-ai-r mixture to the engine;

a fuel chamber means disposed in the body for delivering fuel to the fuel orifice;

an impact tube member interconnecting the fuel chamher and the passage, said impact tube having an outlet open substantially only to the upstream side of the passage upstream of the bridge means;

a suction tube member interconnecting the fuel chamber and said impact tube member having an outlet open substantially only to the downstream side of the passage upstream of the bridge means;

first and second valve means mounted in said impact tube and said suction tube respectively;

a flange portion extending from said air valve means for reducing the pressure in the vicinity of the suction tube outlet; and

control means for closing said first valve means and opening and second valve means in response to throttle valve position to selectively reduce the fuelair mixture ratio.

10. In an air valve carburetor the combination of:

a body having a fuel-air induction passage;

a fuel orifice opening in the passage;

air valve means mounted for reciprocal movement in the passage;

fuel metering means connected to the air valve means, said fuel metering means adapted to cooperate with said orifice to control orifice exposure to pressure in the passage;

a fuel chamber means for supplying fuel to said orifice;

a throttle valve means in the passage for controlling the introduction of the fuelair mixture to the engine;

an impact vent means for communicating said fuel chamber means to substantially induction passage pressure;

a suction vent means for communicating said fuel chamber to a reduced pressure; and

control means for selectively opening and closing said impact vent means and said suction vent means to regulate the fuel-air mixture supplied to the engine.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 1/1964 France.

15 FRANK W. LUTTER, Primary Examiner.

T. R. MILES, Assistant Examiner. 

1. IN AN AIR VALVE CARBURETOR THE COMBINATION OF: A BODY HAVING A FUEL-AIR INDUCTION PASSAGE; A FUEL ORIFICE OPENING IN THE PASSAGE; AIR VALVE MEANS MOUNTED FOR RECIPROCAL MOVEMENT IN THE PASSAGE; FUEL METERING MEANS CONNECTED TO THE AIR VALVE MEANS, SAID FUEL METERING MEANS ADAPTED TO COOPERATE WITH SAID ORIFICE TO CONTROL ORIFICE EXPOSURE TO PRESSURE IN THE PASSAGE; A FUEL CHAMBER MEANS FOR SUPPLYING FUEL TO SAID ORIFICE; A THROTTLE VALVE MEANS IN THE PASSAGE FOR CONTROLLING THE INTRODUCTION OF THE FUEL-AIR MIXTURE TO THE ENGINE; AN IMPACT VENT MEANS FOR COMMUNICATING SAID FUEL CHAMBER MEANS TO SUBSTANTIALLY ATMOSPHERIC PRESSURE; A SUCTION VENT MEANS FOR COMMUNICATING SAID FUEL CHAMBER TO A REDUCED PRESSURE; AND CONTROL MEANS FOR SELECTIVELY OPENING AND CLOSING SAID IMPACT VENT MEANS AND SAID SUCTION VENT MEANS TO REGULATE THE FUEL-AIR MIXTURE SUPPLIED TO THE ENGINE. 